LeetCode Solutions/Problems/96. Unique Binary Search Trees.java
class Solution {
    public int numTrees(int n) {
        int dp[] = new int[n+1];
        dp[1] = 1;
        dp[0] = 1;
        for(int i=2; i<n+1; i++){
            for(int j=0; j<i; j++)
                dp[i] += dp[j]*dp[i-j-1];
        }
        return dp[n];
    }
}